patch-2.4.21 linux-2.4.21/drivers/usb/hcd/ehci-sched.c

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diff -urN linux-2.4.20/drivers/usb/hcd/ehci-sched.c linux-2.4.21/drivers/usb/hcd/ehci-sched.c
@@ -1,1245 +0,0 @@
-/*
- * Copyright (c) 2001-2002 by David Brownell
- * 
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License as published by the
- * Free Software Foundation; either version 2 of the License, or (at your
- * option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
- * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
- * for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software Foundation,
- * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- */
-
-/* this file is part of ehci-hcd.c */
-
-/*-------------------------------------------------------------------------*/
-
-/*
- * EHCI scheduled transaction support:  interrupt, iso, split iso
- * These are called "periodic" transactions in the EHCI spec.
- *
- * Note that for interrupt transfers, the QH/QTD manipulation is shared
- * with the "asynchronous" transaction support (control/bulk transfers).
- * The only real difference is in how interrupt transfers are scheduled.
- * We get some funky API restrictions from the current URB model, which
- * works notably better for reading transfers than for writing.  (And
- * which accordingly needs to change before it'll work inside devices,
- * or with "USB On The Go" additions to USB 2.0 ...)
- */
-
-/*
- * Ceiling microseconds (typical) for that many bytes at high speed
- * ISO is a bit less, no ACK ... from USB 2.0 spec, 5.11.3 (and needed
- * to preallocate bandwidth)
- */
-#define EHCI_HOST_DELAY	5	/* nsec, guess */
-#define HS_USECS(bytes) NS_TO_US ( ((55 * 8 * 2083)/1000) \
-	+ ((2083UL * (3167 + BitTime (bytes)))/1000) \
-	+ EHCI_HOST_DELAY)
-#define HS_USECS_ISO(bytes) NS_TO_US ( ((long)(38 * 8 * 2.083)) \
-	+ ((2083UL * (3167 + BitTime (bytes)))/1000) \
-	+ EHCI_HOST_DELAY)
-	
-static int ehci_get_frame (struct usb_hcd *hcd);
-
-/*-------------------------------------------------------------------------*/
-
-/*
- * periodic_next_shadow - return "next" pointer on shadow list
- * @periodic: host pointer to qh/itd/sitd
- * @tag: hardware tag for type of this record
- */
-static union ehci_shadow *
-periodic_next_shadow (union ehci_shadow *periodic, int tag)
-{
-	switch (tag) {
-	case Q_TYPE_QH:
-		return &periodic->qh->qh_next;
-	case Q_TYPE_FSTN:
-		return &periodic->fstn->fstn_next;
-	case Q_TYPE_ITD:
-		return &periodic->itd->itd_next;
-#ifdef have_split_iso
-	case Q_TYPE_SITD:
-		return &periodic->sitd->sitd_next;
-#endif /* have_split_iso */
-	}
-	dbg ("BAD shadow %p tag %d", periodic->ptr, tag);
-	// BUG ();
-	return 0;
-}
-
-/* returns true after successful unlink */
-/* caller must hold ehci->lock */
-static int periodic_unlink (struct ehci_hcd *ehci, unsigned frame, void *ptr)
-{
-	union ehci_shadow	*prev_p = &ehci->pshadow [frame];
-	u32			*hw_p = &ehci->periodic [frame];
-	union ehci_shadow	here = *prev_p;
-	union ehci_shadow	*next_p;
-
-	/* find predecessor of "ptr"; hw and shadow lists are in sync */
-	while (here.ptr && here.ptr != ptr) {
-		prev_p = periodic_next_shadow (prev_p, Q_NEXT_TYPE (*hw_p));
-		hw_p = &here.qh->hw_next;
-		here = *prev_p;
-	}
-	/* an interrupt entry (at list end) could have been shared */
-	if (!here.ptr) {
-		dbg ("entry %p no longer on frame [%d]", ptr, frame);
-		return 0;
-	}
-	// vdbg ("periodic unlink %p from frame %d", ptr, frame);
-
-	/* update hardware list ... HC may still know the old structure, so
-	 * don't change hw_next until it'll have purged its cache
-	 */
-	next_p = periodic_next_shadow (&here, Q_NEXT_TYPE (*hw_p));
-	*hw_p = here.qh->hw_next;
-
-	/* unlink from shadow list; HCD won't see old structure again */
-	*prev_p = *next_p;
-	next_p->ptr = 0;
-
-	return 1;
-}
-
-/* how many of the uframe's 125 usecs are allocated? */
-static unsigned short
-periodic_usecs (struct ehci_hcd *ehci, unsigned frame, unsigned uframe)
-{
-	u32			*hw_p = &ehci->periodic [frame];
-	union ehci_shadow	*q = &ehci->pshadow [frame];
-	unsigned		usecs = 0;
-
-	while (q->ptr) {
-		switch (Q_NEXT_TYPE (*hw_p)) {
-		case Q_TYPE_QH:
-			/* is it in the S-mask? */
-			if (q->qh->hw_info2 & cpu_to_le32 (1 << uframe))
-				usecs += q->qh->usecs;
-			q = &q->qh->qh_next;
-			break;
-		case Q_TYPE_FSTN:
-			/* for "save place" FSTNs, count the relevant INTR
-			 * bandwidth from the previous frame
-			 */
-			if (q->fstn->hw_prev != EHCI_LIST_END) {
-				dbg ("not counting FSTN bandwidth yet ...");
-			}
-			q = &q->fstn->fstn_next;
-			break;
-		case Q_TYPE_ITD:
-			/* NOTE the "one uframe per itd" policy */
-			if (q->itd->hw_transaction [uframe] != 0)
-				usecs += q->itd->usecs;
-			q = &q->itd->itd_next;
-			break;
-#ifdef have_split_iso
-		case Q_TYPE_SITD:
-			temp = q->sitd->hw_fullspeed_ep &
-				__constant_cpu_to_le32 (1 << 31);
-
-			// FIXME:  this doesn't count data bytes right...
-
-			/* is it in the S-mask?  (count SPLIT, DATA) */
-			if (q->sitd->hw_uframe & cpu_to_le32 (1 << uframe)) {
-				if (temp)
-					usecs += HS_USECS (188);
-				else
-					usecs += HS_USECS (1);
-			}
-
-			/* ... C-mask?  (count CSPLIT, DATA) */
-			if (q->sitd->hw_uframe &
-					cpu_to_le32 (1 << (8 + uframe))) {
-				if (temp)
-					usecs += HS_USECS (0);
-				else
-					usecs += HS_USECS (188);
-			}
-			q = &q->sitd->sitd_next;
-			break;
-#endif /* have_split_iso */
-		default:
-			BUG ();
-		}
-	}
-#ifdef	DEBUG
-	if (usecs > 100)
-		err ("overallocated uframe %d, periodic is %d usecs",
-			frame * 8 + uframe, usecs);
-#endif
-	return usecs;
-}
-
-/*-------------------------------------------------------------------------*/
-
-static void enable_periodic (struct ehci_hcd *ehci)
-{
-	u32	cmd;
-
-	/* did clearing PSE did take effect yet?
-	 * takes effect only at frame boundaries...
-	 */
-	while (readl (&ehci->regs->status) & STS_PSS)
-		udelay (20);
-
-	cmd = readl (&ehci->regs->command) | CMD_PSE;
-	writel (cmd, &ehci->regs->command);
-	/* posted write ... PSS happens later */
-	ehci->hcd.state = USB_STATE_RUNNING;
-
-	/* make sure tasklet scans these */
-	ehci->next_uframe = readl (&ehci->regs->frame_index)
-				% (ehci->periodic_size << 3);
-}
-
-static void disable_periodic (struct ehci_hcd *ehci)
-{
-	u32	cmd;
-
-	/* did setting PSE not take effect yet?
-	 * takes effect only at frame boundaries...
-	 */
-	while (!(readl (&ehci->regs->status) & STS_PSS))
-		udelay (20);
-
-	cmd = readl (&ehci->regs->command) & ~CMD_PSE;
-	writel (cmd, &ehci->regs->command);
-	/* posted write ... */
-
-	ehci->next_uframe = -1;
-}
-
-/*-------------------------------------------------------------------------*/
-
-static void intr_deschedule (
-	struct ehci_hcd	*ehci,
-	unsigned	frame,
-	struct ehci_qh	*qh,
-	unsigned	period
-) {
-	unsigned long	flags;
-
-	period >>= 3;		// FIXME microframe periods not handled yet
-
-	spin_lock_irqsave (&ehci->lock, flags);
-
-	do {
-		periodic_unlink (ehci, frame, qh);
-		qh_put (ehci, qh);
-		frame += period;
-	} while (frame < ehci->periodic_size);
-
-	qh->qh_state = QH_STATE_UNLINK;
-	qh->qh_next.ptr = 0;
-	ehci->periodic_urbs--;
-
-	/* maybe turn off periodic schedule */
-	if (!ehci->periodic_urbs)
-		disable_periodic (ehci);
-	else
-		vdbg ("periodic schedule still enabled");
-
-	spin_unlock_irqrestore (&ehci->lock, flags);
-
-	/*
-	 * If the hc may be looking at this qh, then delay a uframe
-	 * (yeech!) to be sure it's done.
-	 * No other threads may be mucking with this qh.
-	 */
-	if (((ehci_get_frame (&ehci->hcd) - frame) % period) == 0)
-		udelay (125);
-
-	qh->qh_state = QH_STATE_IDLE;
-	qh->hw_next = EHCI_LIST_END;
-
-	vdbg ("descheduled qh %p, per = %d frame = %d count = %d, urbs = %d",
-		qh, period, frame,
-		atomic_read (&qh->refcount), ehci->periodic_urbs);
-}
-
-static int check_period (
-	struct ehci_hcd *ehci, 
-	unsigned	frame,
-	int		uframe,
-	unsigned	period,
-	unsigned	usecs
-) {
-	/*
-	 * 80% periodic == 100 usec/uframe available
-	 * convert "usecs we need" to "max already claimed" 
-	 */
-	usecs = 100 - usecs;
-
-	do {
-		int	claimed;
-
-// FIXME delete when intr_submit handles non-empty queues
-// this gives us a one intr/frame limit (vs N/uframe)
-		if (ehci->pshadow [frame].ptr)
-			return 0;
-
-		claimed = periodic_usecs (ehci, frame, uframe);
-		if (claimed > usecs)
-			return 0;
-
-// FIXME update to handle sub-frame periods
-	} while ((frame += period) < ehci->periodic_size);
-
-	// success!
-	return 1;
-}
-
-static int intr_submit (
-	struct ehci_hcd		*ehci,
-	struct urb		*urb,
-	struct list_head	*qtd_list,
-	int			mem_flags
-) {
-	unsigned		epnum, period;
-	unsigned short		usecs;
-	unsigned long		flags;
-	struct ehci_qh		*qh;
-	struct hcd_dev		*dev;
-	int			status = 0;
-
-	/* get endpoint and transfer data */
-	epnum = usb_pipeendpoint (urb->pipe);
-	if (usb_pipein (urb->pipe))
-		epnum |= 0x10;
-	if (urb->dev->speed != USB_SPEED_HIGH) {
-		dbg ("no intr/tt scheduling yet"); 
-		status = -ENOSYS;
-		goto done;
-	}
-
-	/*
-	 * NOTE: current completion/restart logic doesn't handle more than
-	 * one qtd in a periodic qh ... 16-20 KB/urb is pretty big for this.
-	 * such big requests need many periods to transfer.
-	 *
-	 * FIXME want to change hcd core submit model to expect queuing
-	 * for all transfer types ... not just ISO and (with flag) BULK.
-	 * that means: getting rid of this check; handling the "interrupt
-	 * urb already queued" case below like bulk queuing is handled (no
-	 * errors possible!); and completly getting rid of that annoying
-	 * qh restart logic.  simpler/smaller overall, and more flexible.
-	 */
-	if (unlikely (qtd_list->next != qtd_list->prev)) {
-		dbg ("only one intr qtd per urb allowed"); 
-		status = -EINVAL;
-		goto done;
-	}
-
-	usecs = HS_USECS (urb->transfer_buffer_length);
-
-	/* FIXME handle HS periods of less than 1 frame. */
-	period = urb->interval >> 3;
-	if (period < 1) {
-		dbg ("intr period %d uframes, NYET!", urb->interval);
-		status = -EINVAL;
-		goto done;
-	}
-
-	spin_lock_irqsave (&ehci->lock, flags);
-
-	/* get the qh (must be empty and idle) */
-	dev = (struct hcd_dev *)urb->dev->hcpriv;
-	qh = (struct ehci_qh *) dev->ep [epnum];
-	if (qh) {
-		/* only allow one queued interrupt urb per EP */
-		if (unlikely (qh->qh_state != QH_STATE_IDLE
-				|| !list_empty (&qh->qtd_list))) {
-			dbg ("interrupt urb already queued");
-			status = -EBUSY;
-		} else {
-			/* maybe reset hardware's data toggle in the qh */
-			if (unlikely (!usb_gettoggle (urb->dev, epnum & 0x0f,
-					!(epnum & 0x10)))) {
-				qh->hw_token |=
-					__constant_cpu_to_le32 (QTD_TOGGLE);
-				usb_settoggle (urb->dev, epnum & 0x0f,
-					!(epnum & 0x10), 1);
-			}
-			/* trust the QH was set up as interrupt ... */
-			list_splice (qtd_list, &qh->qtd_list);
-			qh_update (qh, list_entry (qtd_list->next,
-						struct ehci_qtd, qtd_list));
-			qtd_list = &qh->qtd_list;
-		}
-	} else {
-		/* can't sleep here, we have ehci->lock... */
-		qh = ehci_qh_make (ehci, urb, qtd_list, SLAB_ATOMIC);
-		if (likely (qh != 0)) {
-			// dbg ("new INTR qh %p", qh);
-			dev->ep [epnum] = qh;
-			qtd_list = &qh->qtd_list;
-		} else
-			status = -ENOMEM;
-	}
-
-	/* Schedule this periodic QH. */
-	if (likely (status == 0)) {
-		unsigned	frame = period;
-
-		qh->hw_next = EHCI_LIST_END;
-		qh->usecs = usecs;
-
-		urb->hcpriv = qh_get (qh);
-		status = -ENOSPC;
-
-		/* pick a set of schedule slots, link the QH into them */
-		do {
-			int	uframe;
-
-			/* pick a set of slots such that all uframes have
-			 * enough periodic bandwidth available.
-			 *
-			 * FIXME for TT splits, need uframes for start and end.
-			 * FSTNs can put end into next frame (uframes 0 or 1).
-			 */
-			frame--;
-			for (uframe = 0; uframe < 8; uframe++) {
-				if (check_period (ehci, frame, uframe,
-						period, usecs) != 0)
-					break;
-			}
-			if (uframe == 8)
-				continue;
-
-			/* QH will run once each period, starting there  */
-			urb->start_frame = frame;
-			status = 0;
-
-			/* set S-frame mask */
-			qh->hw_info2 |= cpu_to_le32 (1 << uframe);
-			// dbg_qh ("Schedule INTR qh", ehci, qh);
-
-			/* stuff into the periodic schedule */
-			qh->qh_state = QH_STATE_LINKED;
-			vdbg ("qh %p usecs %d period %d starting %d.%d",
-				qh, qh->usecs, period, frame, uframe);
-			do {
-				if (unlikely (ehci->pshadow [frame].ptr != 0)) {
-// FIXME -- just link toward the end, before any qh with a shorter period,
-// AND handle it already being (implicitly) linked into this frame
-// AS WELL AS updating the check_period() logic
-					BUG ();
-				} else {
-					ehci->pshadow [frame].qh = qh_get (qh);
-					ehci->periodic [frame] =
-						QH_NEXT (qh->qh_dma);
-				}
-				wmb ();
-				frame += period;
-			} while (frame < ehci->periodic_size);
-
-			/* update bandwidth utilization records (for usbfs) */
-			usb_claim_bandwidth (urb->dev, urb, usecs/period, 0);
-
-			/* maybe enable periodic schedule processing */
-			if (!ehci->periodic_urbs++)
-				enable_periodic (ehci);
-			break;
-
-		} while (frame);
-	}
-	spin_unlock_irqrestore (&ehci->lock, flags);
-done:
-	if (status)
-		qtd_list_free (ehci, urb, qtd_list);
-
-	return status;
-}
-
-static unsigned long
-intr_complete (
-	struct ehci_hcd	*ehci,
-	unsigned	frame,
-	struct ehci_qh	*qh,
-	unsigned long	flags		/* caller owns ehci->lock ... */
-) {
-	struct ehci_qtd	*qtd;
-	struct urb	*urb;
-	int		unlinking;
-
-	/* nothing to report? */
-	if (likely ((qh->hw_token & __constant_cpu_to_le32 (QTD_STS_ACTIVE))
-			!= 0))
-		return flags;
-	if (unlikely (list_empty (&qh->qtd_list))) {
-		dbg ("intr qh %p no TDs?", qh);
-		return flags;
-	}
-	
-	qtd = list_entry (qh->qtd_list.next, struct ehci_qtd, qtd_list);
-	urb = qtd->urb;
-	unlinking = (urb->status == -ENOENT) || (urb->status == -ECONNRESET);
-
-	/* call any completions, after patching for reactivation */
-	spin_unlock_irqrestore (&ehci->lock, flags);
-	/* NOTE:  currently restricted to one qtd per qh! */
-	if (qh_completions (ehci, qh, 0) == 0)
-		urb = 0;
-	spin_lock_irqsave (&ehci->lock, flags);
-
-	/* never reactivate requests that were unlinked ... */
-	if (likely (urb != 0)) {
-		if (unlinking
-				|| urb->status == -ECONNRESET
-				|| urb->status == -ENOENT
-				// || (urb->dev == null)
-				|| ehci->hcd.state == USB_STATE_HALT)
-			urb = 0;
-		// FIXME look at all those unlink cases ... we always
-		// need exactly one completion that reports unlink.
-		// the one above might not have been it!
-	}
-
-	/* normally reactivate */
-	if (likely (urb != 0)) {
-		if (usb_pipeout (urb->pipe))
-			pci_dma_sync_single (ehci->hcd.pdev,
-				qtd->buf_dma,
-				urb->transfer_buffer_length,
-				PCI_DMA_TODEVICE);
-		urb->status = -EINPROGRESS;
-		urb->actual_length = 0;
-
-		/* patch qh and restart */
-		qh_update (qh, qtd);
-	}
-	return flags;
-}
-
-/*-------------------------------------------------------------------------*/
-
-static void
-itd_free_list (struct ehci_hcd *ehci, struct urb *urb)
-{
-	struct ehci_itd *first_itd = urb->hcpriv;
-
-	pci_unmap_single (ehci->hcd.pdev,
-		first_itd->buf_dma, urb->transfer_buffer_length,
-		usb_pipein (urb->pipe)
-		    ? PCI_DMA_FROMDEVICE
-		    : PCI_DMA_TODEVICE);
-	while (!list_empty (&first_itd->itd_list)) {
-		struct ehci_itd	*itd;
-
-		itd = list_entry (
-			first_itd->itd_list.next,
-			struct ehci_itd, itd_list);
-		list_del (&itd->itd_list);
-		pci_pool_free (ehci->itd_pool, itd, itd->itd_dma);
-	}
-	pci_pool_free (ehci->itd_pool, first_itd, first_itd->itd_dma);
-	urb->hcpriv = 0;
-}
-
-static int
-itd_fill (
-	struct ehci_hcd	*ehci,
-	struct ehci_itd	*itd,
-	struct urb	*urb,
-	unsigned	index,		// urb->iso_frame_desc [index]
-	dma_addr_t	dma		// mapped transfer buffer
-) {
-	u64		temp;
-	u32		buf1;
-	unsigned	i, epnum, maxp, multi;
-	unsigned	length;
-
-	itd->hw_next = EHCI_LIST_END;
-	itd->urb = urb;
-	itd->index = index;
-
-	/* tell itd about its transfer buffer, max 2 pages */
-	length = urb->iso_frame_desc [index].length;
-	dma += urb->iso_frame_desc [index].offset;
-	temp = dma & ~0x0fff;
-	for (i = 0; i < 2; i++) {
-		itd->hw_bufp [i] = cpu_to_le32 ((u32) temp);
-		itd->hw_bufp_hi [i] = cpu_to_le32 ((u32)(temp >> 32));
-		temp += 0x1000;
-	}
-	itd->buf_dma = dma;
-
-	/*
-	 * this might be a "high bandwidth" highspeed endpoint,
-	 * as encoded in the ep descriptor's maxpacket field
-	 */
-	epnum = usb_pipeendpoint (urb->pipe);
-	if (usb_pipein (urb->pipe)) {
-		maxp = urb->dev->epmaxpacketin [epnum];
-		buf1 = (1 << 11);
-	} else {
-		maxp = urb->dev->epmaxpacketout [epnum];
-		buf1 = 0;
-	}
-	buf1 |= (maxp & 0x03ff);
-	multi = 1;
-	multi += (maxp >> 11) & 0x03;
-	maxp &= 0x03ff;
-	maxp *= multi;
-
-	/* transfer can't fit in any uframe? */ 
-	if (length < 0 || maxp < length) {
-		dbg ("BAD iso packet: %d bytes, max %d, urb %p [%d] (of %d)",
-			length, maxp, urb, index,
-			urb->iso_frame_desc [index].length);
-		return -ENOSPC;
-	}
-	itd->usecs = HS_USECS_ISO (length);
-
-	/* "plus" info in low order bits of buffer pointers */
-	itd->hw_bufp [0] |= cpu_to_le32 ((epnum << 8) | urb->dev->devnum);
-	itd->hw_bufp [1] |= cpu_to_le32 (buf1);
-	itd->hw_bufp [2] |= cpu_to_le32 (multi);
-
-	/* figure hw_transaction[] value (it's scheduled later) */
-	itd->transaction = EHCI_ISOC_ACTIVE;
-	itd->transaction |= dma & 0x0fff;		/* offset; buffer=0 */
-	if ((index + 1) == urb->number_of_packets)
-		itd->transaction |= EHCI_ITD_IOC; 	/* end-of-urb irq */
-	itd->transaction |= length << 16;
-	cpu_to_le32s (&itd->transaction);
-
-	return 0;
-}
-
-static int
-itd_urb_transaction (
-	struct ehci_hcd		*ehci,
-	struct urb		*urb,
-	int			mem_flags
-) {
-	int			frame_index;
-	struct ehci_itd		*first_itd, *itd;
-	int			status;
-	dma_addr_t		buf_dma, itd_dma;
-
-	/* set up one dma mapping for this urb */
-	buf_dma = pci_map_single (ehci->hcd.pdev,
-		urb->transfer_buffer, urb->transfer_buffer_length,
-		usb_pipein (urb->pipe)
-		    ? PCI_DMA_FROMDEVICE
-		    : PCI_DMA_TODEVICE);
-	if (buf_dma == 0)
-		return -ENOMEM;
-
-	/* allocate/init ITDs */
-	for (frame_index = 0, first_itd = 0;
-			frame_index < urb->number_of_packets;
-			frame_index++) {
-		itd = pci_pool_alloc (ehci->itd_pool, mem_flags, &itd_dma);
-		if (!itd) {
-			status = -ENOMEM;
-			goto fail;
-		}
-		memset (itd, 0, sizeof *itd);
-		itd->itd_dma = itd_dma;
-
-		status = itd_fill (ehci, itd, urb, frame_index, buf_dma);
-		if (status != 0)
-			goto fail;
-
-		if (first_itd)
-			list_add_tail (&itd->itd_list,
-					&first_itd->itd_list);
-		else {
-			INIT_LIST_HEAD (&itd->itd_list);
-			urb->hcpriv = first_itd = itd;
-		}
-	}
-	urb->error_count = 0;
-	return 0;
-
-fail:
-	if (urb->hcpriv)
-		itd_free_list (ehci, urb);
-	return status;
-}
-
-/*-------------------------------------------------------------------------*/
-
-static inline void
-itd_link (struct ehci_hcd *ehci, unsigned frame, struct ehci_itd *itd)
-{
-	/* always prepend ITD/SITD ... only QH tree is order-sensitive */
-	itd->itd_next = ehci->pshadow [frame];
-	itd->hw_next = ehci->periodic [frame];
-	ehci->pshadow [frame].itd = itd;
-	ehci->periodic [frame] = cpu_to_le32 (itd->itd_dma) | Q_TYPE_ITD;
-}
-
-/*
- * return zero on success, else -errno
- * - start holds first uframe to start scheduling into
- * - max is the first uframe it's NOT (!) OK to start scheduling into
- * math to be done modulo "mod" (ehci->periodic_size << 3)
- */
-static int get_iso_range (
-	struct ehci_hcd		*ehci,
-	struct urb		*urb,
-	unsigned		*start,
-	unsigned		*max,
-	unsigned		mod
-) {
-	struct list_head	*lh;
-	struct hcd_dev		*dev = urb->dev->hcpriv;
-	int			last = -1;
-	unsigned		now, span, end;
-
-	span = urb->interval * urb->number_of_packets;
-
-	/* first see if we know when the next transfer SHOULD happen */
-	list_for_each (lh, &dev->urb_list) {
-		struct urb	*u;
-		struct ehci_itd	*itd;
-		unsigned	s;
-
-		u = list_entry (lh, struct urb, urb_list);
-		if (u == urb || u->pipe != urb->pipe)
-			continue;
-		if (u->interval != urb->interval) {	/* must not change! */ 
-			dbg ("urb %p interval %d ... != %p interval %d",
-				u, u->interval, urb, urb->interval);
-			return -EINVAL;
-		}
-		
-		/* URB for this endpoint... covers through when?  */
-		itd = urb->hcpriv;
-		s = itd->uframe + u->interval * u->number_of_packets;
-		if (last < 0)
-			last = s;
-		else {
-			/*
-			 * So far we can only queue two ISO URBs...
-			 *
-			 * FIXME do interval math, figure out whether
-			 * this URB is "before" or not ... also, handle
-			 * the case where the URB might have completed,
-			 * but hasn't yet been processed.
-			 */
-			dbg ("NYET: queue >2 URBs per ISO endpoint");
-			return -EDOM;
-		}
-	}
-
-	/* calculate the legal range [start,max) */
-	now = readl (&ehci->regs->frame_index) + 1;	/* next uframe */
-	if (!ehci->periodic_urbs)
-		now += 8;				/* startup delay */
-	now %= mod;
-	end = now + mod;
-	if (last < 0) {
-		*start = now + ehci->i_thresh + /* paranoia */ 1;
-		*max = end - span;
-		if (*max < *start + 1)
-			*max = *start + 1;
-	} else {
-		*start = last % mod;
-		*max = (last + 1) % mod;
-	}
-
-	/* explicit start frame? */
-	if (!(urb->transfer_flags & USB_ISO_ASAP)) {
-		unsigned	temp;
-
-		/* sanity check: must be in range */
-		urb->start_frame %= ehci->periodic_size;
-		temp = urb->start_frame << 3;
-		if (temp < *start)
-			temp += mod;
-		if (temp > *max)
-			return -EDOM;
-
-		/* use that explicit start frame */
-		*start = urb->start_frame << 3;
-		temp += 8;
-		if (temp < *max)
-			*max = temp;
-	}
-
-	// FIXME minimize wraparound to "now" ... insist max+span
-	// (and start+span) remains a few frames short of "end"
-
-	*max %= ehci->periodic_size;
-	if ((*start + span) < end)
-		return 0;
-	return -EFBIG;
-}
-
-static int
-itd_schedule (struct ehci_hcd *ehci, struct urb *urb)
-{
-	unsigned	start, max, i;
-	int		status;
-	unsigned	mod = ehci->periodic_size << 3;
-
-	for (i = 0; i < urb->number_of_packets; i++) {
-		urb->iso_frame_desc [i].status = -EINPROGRESS;
-		urb->iso_frame_desc [i].actual_length = 0;
-	}
-
-	if ((status = get_iso_range (ehci, urb, &start, &max, mod)) != 0)
-		return status;
-
-	do {
-		unsigned	uframe;
-		unsigned	usecs;
-		struct ehci_itd	*itd;
-
-		/* check schedule: enough space? */
-		itd = urb->hcpriv;
-		uframe = start;
-		for (i = 0, uframe = start;
-				i < urb->number_of_packets;
-				i++, uframe += urb->interval) {
-			uframe %= mod;
-
-			/* can't commit more than 80% periodic == 100 usec */
-			if (periodic_usecs (ehci, uframe >> 3, uframe & 0x7)
-					> (100 - itd->usecs)) {
-				itd = 0;
-				break;
-			}
-			itd = list_entry (itd->itd_list.next,
-				struct ehci_itd, itd_list);
-		}
-		if (!itd)
-			continue;
-		
-		/* that's where we'll schedule this! */
-		itd = urb->hcpriv;
-		urb->start_frame = start >> 3;
-		vdbg ("ISO urb %p (%d packets period %d) starting %d.%d",
-			urb, urb->number_of_packets, urb->interval,
-			urb->start_frame, start & 0x7);
-		for (i = 0, uframe = start, usecs = 0;
-				i < urb->number_of_packets;
-				i++, uframe += urb->interval) {
-			uframe %= mod;
-
-			itd->uframe = uframe;
-			itd->hw_transaction [uframe & 0x07] = itd->transaction;
-			itd_link (ehci, (uframe >> 3) % ehci->periodic_size,
-				itd);
-			wmb ();
-			usecs += itd->usecs;
-
-			itd = list_entry (itd->itd_list.next,
-				struct ehci_itd, itd_list);
-		}
-
-		/* update bandwidth utilization records (for usbfs)
-		 *
-		 * FIXME This claims each URB queued to an endpoint, as if
-		 * transfers were concurrent, not sequential.  So bandwidth
-		 * typically gets double-billed ... comes from tying it to
-		 * URBs rather than endpoints in the schedule.  Luckily we
-		 * don't use this usbfs data for serious decision making.
-		 */
-		usecs /= urb->number_of_packets;
-		usecs /= urb->interval;
-		usecs >>= 3;
-		if (usecs < 1)
-			usecs = 1;
-		usb_claim_bandwidth (urb->dev, urb, usecs, 1);
-
-		/* maybe enable periodic schedule processing */
-		if (!ehci->periodic_urbs++)
-			enable_periodic (ehci);
-
-		return 0;
-
-	} while ((start = ++start % mod) != max);
-
-	/* no room in the schedule */
-	dbg ("urb %p, CAN'T SCHEDULE", urb);
-	return -ENOSPC;
-}
-
-/*-------------------------------------------------------------------------*/
-
-#define	ISO_ERRS (EHCI_ISOC_BUF_ERR | EHCI_ISOC_BABBLE | EHCI_ISOC_XACTERR)
-
-static unsigned long
-itd_complete (
-	struct ehci_hcd	*ehci,
-	struct ehci_itd	*itd,
-	unsigned	uframe,
-	unsigned long	flags
-) {
-	struct urb				*urb = itd->urb;
-	struct iso_packet_descriptor		*desc;
-	u32					t;
-
-	/* update status for this uframe's transfers */
-	desc = &urb->iso_frame_desc [itd->index];
-
-	t = itd->hw_transaction [uframe];
-	itd->hw_transaction [uframe] = 0;
-	if (t & EHCI_ISOC_ACTIVE)
-		desc->status = -EXDEV;
-	else if (t & ISO_ERRS) {
-		urb->error_count++;
-		if (t & EHCI_ISOC_BUF_ERR)
-			desc->status = usb_pipein (urb->pipe)
-				? -ENOSR  /* couldn't read */
-				: -ECOMM; /* couldn't write */
-		else if (t & EHCI_ISOC_BABBLE)
-			desc->status = -EOVERFLOW;
-		else /* (t & EHCI_ISOC_XACTERR) */
-			desc->status = -EPROTO;
-
-		/* HC need not update length with this error */
-		if (!(t & EHCI_ISOC_BABBLE))
-			desc->actual_length += EHCI_ITD_LENGTH (t);
-	} else {
-		desc->status = 0;
-		desc->actual_length += EHCI_ITD_LENGTH (t);
-	}
-
-	vdbg ("itd %p urb %p packet %d/%d trans %x status %d len %d",
-		itd, urb, itd->index + 1, urb->number_of_packets,
-		t, desc->status, desc->actual_length);
-
-	/* handle completion now? */
-	if ((itd->index + 1) != urb->number_of_packets)
-		return flags;
-
-	/*
-	 * Always give the urb back to the driver ... expect it to submit
-	 * a new urb (or resubmit this), and to have another already queued
-	 * when un-interrupted transfers are needed.
-	 *
-	 * NOTE that for now we don't accelerate ISO unlinks; they just
-	 * happen according to the current schedule.  Means a delay of
-	 * up to about a second (max).
-	 */
-	itd_free_list (ehci, urb);
-	if (urb->status == -EINPROGRESS)
-		urb->status = 0;
-
-	spin_unlock_irqrestore (&ehci->lock, flags);
-	usb_hcd_giveback_urb (&ehci->hcd, urb);
-	spin_lock_irqsave (&ehci->lock, flags);
-
-	/* defer stopping schedule; completion can submit */
-	ehci->periodic_urbs--;
-	if (!ehci->periodic_urbs)
-		disable_periodic (ehci);
-
-	return flags;
-}
-
-/*-------------------------------------------------------------------------*/
-
-static int itd_submit (struct ehci_hcd *ehci, struct urb *urb, int mem_flags)
-{
-	int		status;
-	unsigned long	flags;
-
-	dbg ("itd_submit urb %p", urb);
-
-	/* NOTE DMA mapping assumes this ... */
-	if (urb->iso_frame_desc [0].offset != 0)
-		return -EINVAL;
-	
-	/* allocate ITDs w/o locking anything */
-	status = itd_urb_transaction (ehci, urb, mem_flags);
-	if (status < 0)
-		return status;
-
-	/* schedule ... need to lock */
-	spin_lock_irqsave (&ehci->lock, flags);
-	status = itd_schedule (ehci, urb);
-	spin_unlock_irqrestore (&ehci->lock, flags);
-	if (status < 0)
-		itd_free_list (ehci, urb);
-
-	return status;
-}
-
-#ifdef have_split_iso
-
-/*-------------------------------------------------------------------------*/
-
-/*
- * "Split ISO TDs" ... used for USB 1.1 devices going through
- * the TTs in USB 2.0 hubs.
- */
-
-static void
-sitd_free (struct ehci_hcd *ehci, struct ehci_sitd *sitd)
-{
-	pci_pool_free (ehci->sitd_pool, sitd, sitd->sitd_dma);
-}
-
-static struct ehci_sitd *
-sitd_make (
-	struct ehci_hcd	*ehci,
-	struct urb	*urb,
-	unsigned	index,		// urb->iso_frame_desc [index]
-	unsigned	uframe,		// scheduled start
-	dma_addr_t	dma,		// mapped transfer buffer
-	int		mem_flags
-) {
-	struct ehci_sitd	*sitd;
-	unsigned		length;
-
-	sitd = pci_pool_alloc (ehci->sitd_pool, mem_flags, &dma);
-	if (!sitd)
-		return sitd;
-	sitd->urb = urb;
-	length = urb->iso_frame_desc [index].length;
-	dma += urb->iso_frame_desc [index].offset;
-
-#if 0
-	// FIXME:  do the rest!
-#else
-	sitd_free (ehci, sitd);
-	return 0;
-#endif
-
-}
-
-static void
-sitd_link (struct ehci_hcd *ehci, unsigned frame, struct ehci_sitd *sitd)
-{
-	u32		ptr;
-
-	ptr = cpu_to_le32 (sitd->sitd_dma | 2);	// type 2 == sitd
-	if (ehci->pshadow [frame].ptr) {
-		if (!sitd->sitd_next.ptr) {
-			sitd->sitd_next = ehci->pshadow [frame];
-			sitd->hw_next = ehci->periodic [frame];
-		} else if (sitd->sitd_next.ptr != ehci->pshadow [frame].ptr) {
-			dbg ("frame %d sitd link goof", frame);
-			BUG ();
-		}
-	}
-	ehci->pshadow [frame].sitd = sitd;
-	ehci->periodic [frame] = ptr;
-}
-
-static unsigned long
-sitd_complete (
-	struct ehci_hcd *ehci,
-	struct ehci_sitd	*sitd,
-	unsigned long		flags
-) {
-	// FIXME -- implement!
-
-	dbg ("NYI -- sitd_complete");
-	return flags;
-}
-
-/*-------------------------------------------------------------------------*/
-
-static int sitd_submit (struct ehci_hcd *ehci, struct urb *urb, int mem_flags)
-{
-	// struct ehci_sitd	*first_sitd = 0;
-	unsigned		frame_index;
-	dma_addr_t		dma;
-
-	dbg ("NYI -- sitd_submit");
-
-	// FIXME -- implement!
-
-	// FIXME:  setup one big dma mapping
-	dma = 0;
-
-	for (frame_index = 0;
-			frame_index < urb->number_of_packets;
-			frame_index++) {
-		struct ehci_sitd	*sitd;
-		unsigned		uframe;
-
-		// FIXME:  use real arguments, schedule this!
-		uframe = -1;
-
-		sitd = sitd_make (ehci, urb, frame_index,
-				uframe, dma, mem_flags);
-
-		if (sitd) {
-    /*
-			if (first_sitd)
-				list_add_tail (&sitd->sitd_list,
-						&first_sitd->sitd_list);
-			else
-				first_sitd = sitd;
-    */
-		} else {
-			// FIXME:  clean everything up
-		}
-	}
-
-	// if we have a first sitd, then
-		// store them all into the periodic schedule!
-		// urb->hcpriv = first sitd in sitd_list
-
-	return -ENOSYS;
-}
-#endif /* have_split_iso */
-
-/*-------------------------------------------------------------------------*/
-
-static void scan_periodic (struct ehci_hcd *ehci)
-{
-	unsigned	frame, clock, now_uframe, mod;
-	unsigned long	flags;
-
-	mod = ehci->periodic_size << 3;
-	spin_lock_irqsave (&ehci->lock, flags);
-
-	/*
-	 * When running, scan from last scan point up to "now"
-	 * else clean up by scanning everything that's left.
-	 * Touches as few pages as possible:  cache-friendly.
-	 * Don't scan ISO entries more than once, though.
-	 */
-	frame = ehci->next_uframe >> 3;
-	if (HCD_IS_RUNNING (ehci->hcd.state))
-		now_uframe = readl (&ehci->regs->frame_index);
-	else
-		now_uframe = (frame << 3) - 1;
-	now_uframe %= mod;
-	clock = now_uframe >> 3;
-
-	for (;;) {
-		union ehci_shadow	q, *q_p;
-		u32			type, *hw_p;
-		unsigned		uframes;
-
-restart:
-		/* scan schedule to _before_ current frame index */
-		if (frame == clock)
-			uframes = now_uframe & 0x07;
-		else
-			uframes = 8;
-
-		q_p = &ehci->pshadow [frame];
-		hw_p = &ehci->periodic [frame];
-		q.ptr = q_p->ptr;
-		type = Q_NEXT_TYPE (*hw_p);
-
-		/* scan each element in frame's queue for completions */
-		while (q.ptr != 0) {
-			int			last;
-			unsigned		uf;
-			union ehci_shadow	temp;
-
-			switch (type) {
-			case Q_TYPE_QH:
-				last = (q.qh->hw_next == EHCI_LIST_END);
-				temp = q.qh->qh_next;
-				type = Q_NEXT_TYPE (q.qh->hw_next);
-				flags = intr_complete (ehci, frame,
-						qh_get (q.qh), flags);
-				qh_put (ehci, q.qh);
-				q = temp;
-				break;
-			case Q_TYPE_FSTN:
-				last = (q.fstn->hw_next == EHCI_LIST_END);
-				/* for "save place" FSTNs, look at QH entries
-				 * in the previous frame for completions.
-				 */
-				if (q.fstn->hw_prev != EHCI_LIST_END) {
-					dbg ("ignoring completions from FSTNs");
-				}
-				type = Q_NEXT_TYPE (q.fstn->hw_next);
-				q = q.fstn->fstn_next;
-				break;
-			case Q_TYPE_ITD:
-				last = (q.itd->hw_next == EHCI_LIST_END);
-
-				/* Unlink each (S)ITD we see, since the ISO
-				 * URB model forces constant rescheduling.
-				 * That complicates sharing uframes in ITDs,
-				 * and means we need to skip uframes the HC
-				 * hasn't yet processed.
-				 */
-				for (uf = 0; uf < uframes; uf++) {
-					if (q.itd->hw_transaction [uf] != 0) {
-						temp = q;
-						*q_p = q.itd->itd_next;
-						*hw_p = q.itd->hw_next;
-						type = Q_NEXT_TYPE (*hw_p);
-
-						/* might free q.itd ... */
-						flags = itd_complete (ehci,
-							temp.itd, uf, flags);
-						break;
-					}
-				}
-				/* we might skip this ITD's uframe ... */
-				if (uf == uframes) {
-					q_p = &q.itd->itd_next;
-					hw_p = &q.itd->hw_next;
-					type = Q_NEXT_TYPE (q.itd->hw_next);
-				}
-
-				q = *q_p;
-				break;
-#ifdef have_split_iso
-			case Q_TYPE_SITD:
-				last = (q.sitd->hw_next == EHCI_LIST_END);
-				flags = sitd_complete (ehci, q.sitd, flags);
-				type = Q_NEXT_TYPE (q.sitd->hw_next);
-
-				// FIXME unlink SITD after split completes
-				q = q.sitd->sitd_next;
-				break;
-#endif /* have_split_iso */
-			default:
-				dbg ("corrupt type %d frame %d shadow %p",
-					type, frame, q.ptr);
-				// BUG ();
-				last = 1;
-				q.ptr = 0;
-			}
-
-			/* did completion remove an interior q entry? */
-			if (unlikely (q.ptr == 0 && !last))
-				goto restart;
-		}
-
-		/* stop when we catch up to the HC */
-
-		// FIXME:  this assumes we won't get lapped when
-		// latencies climb; that should be rare, but...
-		// detect it, and just go all the way around.
-		// FLR might help detect this case, so long as latencies
-		// don't exceed periodic_size msec (default 1.024 sec).
-
-		// FIXME:  likewise assumes HC doesn't halt mid-scan
-
-		if (frame == clock) {
-			unsigned	now;
-
-			if (!HCD_IS_RUNNING (ehci->hcd.state))
-				break;
-			ehci->next_uframe = now_uframe;
-			now = readl (&ehci->regs->frame_index) % mod;
-			if (now_uframe == now)
-				break;
-
-			/* rescan the rest of this frame, then ... */
-			now_uframe = now;
-			clock = now_uframe >> 3;
-		} else
-			frame = (frame + 1) % ehci->periodic_size;
-	} 
-	spin_unlock_irqrestore (&ehci->lock, flags);
-}
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)